Psychomotor Vigilance Impairment During Total Sleep Deprivation Is Exacerbated in Sleep-Onset Insomnia

Figures & data

Table 1 Participant Characteristics

	Sleep-Onset Insomnia Group	Healthy Control Group
N	7	7
Age (y)	29.0 ± 6.2	29.0 ± 6.6
Gender (M, F)	1, 6	3, 4
Body Mass Index (kg/m^2)	26.3 ± 6.1	25.1 ± 2.1
Habitual caffeine use (drinks per day)	0.8 ± 0.6	0.9 ± 0.8
Epworth Sleepiness Scale	8.0 ± 4.6*	3.0 ± 1.0
Composite Scale of Morningness	37.0 ± 6.6	39.4 ± 5.3
Pittsburg Sleep Quality Index	10.4 ± 3.1***	2.0 ± 1.0
Insomnia Severity Index	28.0 ± 9.1	–
Sleep history (sleep diary)
Time in bed (h)	9.2 ± 2.1	8.3 ± 0.8
Sleep duration (h)	6.5 ± 0.8	7.3 ± 0.7
Sleep efficiency (%)	72.5 ± 13.1***	88.0 ± 2.7
Sleep latency (h)	1.8 ± 1.6*	0.2 ± 0.1
Intermittent wakefulness (h)	0.9 ± 0.3	0.8 ± 0.3
Sleep history (actigraphy)
Sleep duration (h)	7.0 ± 0.8	7.0 ± 0.8
Bedtime (h)	22:09 ± 0.6**	22:53 ± 1.3
Waketime (h)	07:07 ± 1.9	07:19 ± 0.8
Baseline in-laboratory sleep (PSG)
Time in bed (h)	10.0	10.0
Total sleep time (h)	9.1 ± 0.4	9.1 ± 0.5
Sleep efficiency (%)	91.1 ± 3.5	91.0 ± 5.1
Sleep latency (h)	0.3 ± 0.3	0.3 ± 0.2
WASO (h)	0.6 ± 0.3	0.7 ± 0.4

Notes: Means (± SD) are shown. Group differences were assessed by independent samples t-test.

Abbreviations: *P < 0.05, **P < 0.01, ***P < 0.001; PSG, polysomnography; WASO, wakefulness after sleep onset.

Figure 1 Schematic of the 5-day (4-night) laboratory study protocol.

Notes: Participants entered the laboratory at 14:00 on day 1 and remained in the laboratory until 14:00 on day 5. Distinct phases of the study are indicated above the schematic. The tick marks below the schematic indicate the study start and end times (14:00) and the bedtimes (22:00) and wake-up times (08:00). All other indicated clock times mark the start times of performance test blocks. Black: scheduled sleep; gray: performance testing.

Figure 2 Psychomotor vigilance test results.

Notes: Means ± SE for lapses of attention (top), mean RT (middle), and false starts (bottom) on the 10 min PVT (left) and the 3 min PVT (right) across 38 h of total sleep deprivation and following recovery sleep. Data are plotted against the start times of performance test blocks. Cumulative time awake is shown across the top. Black: sleep-onset insomniacs; gray: healthy normal sleepers. Gray vertical bars: recovery sleep.
Abbreviations: PVT, psychomotor vigilance test; RT, reaction time.

Table 2 F Statistics for Analyses of PVT Outcome Measures

	Lapses		Mean RT		False Starts
	10 min PVT	3 min PVT	10 min PVT	3 min PVT	10 min PVT	3 min PVT
Main effect, group	22.42***	22.45***	13.66***	17.40***	36.55***	1.16
Main effect, test block	11.95***	5.06***	9.78***	8.67***	4.25***	3.29***
Interaction, group by test block	0.96	1.36	1.48	1.07	2.14*	0.44
Main effect, group	5.57*	2.78	5.81*	1.60	13.27***	14.02***
Main effect, test block	7.35***	1.88*	7.26***	4.07***	3.51***	3.38***
Interaction, group by test block	0.80	0.35	1.67	0.35	1.87*	0.47
Main effect, sex	2.93	7.38**	1.35	15.05***	0.01	15.38***
Interaction, group by sex	0.17	1.53	0.26	0.19	1.93	8.11**
Interaction, bout by sex	0.36	0.87	0.44	1.18	1.05	0.56
Interaction, group by test block by sex	0.34	0.23	0.76	0.39	0.61	0.91

Notes: Top section, primary analysis; bottom section, secondary analysis controlling for sex. *P < 0.05, **P < 0.01, ***P < 0.001. PVT = psychomotor vigilance test; RT = response time.

Figure 3 Time-on-task results.

Notes: Means ± SE for RT in 1 min bins on the 10 min PVT (left) and the 3 min PVT (right) across 38 h of total sleep deprivation and following recovery sleep. Data are plotted against the start times of the test blocks; placement of the 1 min bins in each test block is not to scale on the clock time axis. Cumulative time awake is shown across the top. Note the difference in vertical scale between the graphs on the left (10 min PVT) versus right (3 min PVT). Black (top graphs): sleep-onset insomniacs; gray (bottom graphs): healthy normal sleepers. Gray vertical bars: recovery sleep.
Abbreviations: PVT, psychomotor vigilance test; RT, reaction time.